Turbine engines are commonly used in the electrical power generation industry. Such turbine engines include a compressor section where air which has been drawn into the turbine engine is compressed. The compressed air is mixed with fuel and burned in a combustor section. The hot expanding combustion gases are then routed into a turbine section which provides the motive power generated by the turbine engine.
The compressor section of the turbine engine includes alternating rows of stator vanes and compressor blades. The compressor blades are mounted on a rotating shaft of the turbine engine. The stator vanes are attached to the housing of the compressor. Each row of stator vanes helps to direct the air flowing through the compressor into the next row of compressor blades at an angle designed to facilitate compression of the incoming air.
The turbine section of the engine also includes a plurality of alternating rows of stator vanes and turbine blades. The turbine blades are also attached to the shaft of the engine. The stator vanes are attached to the housing of the turbine section of the engine. Each row of the stator vanes helps to direct the hot combustion gases onto the next row of turbine blades at an angle that facilitates the generation of power by the turbine section.
Although the stator vanes, compressor blades and turbine blades are made up of highly durable materials, over an extended period of time air and moisture flowing at high speed and at high volumes over the blades can cause the material of the blades to erode. In some instances, small particles such as dust and sand in the air passing through a turbine can also contribute to erosion of the blades. Similarly, the hot combustion gases can cause the turbine blades in the turbine section to erode as well. In the compressor section, water or water vapor may be injected into the flow of air passing through the compressor to help clean the compressor section and/or to cool the air. The water droplets or water vapor within the airflow can cause blade erosion.
Excessive erosion of compressor and turbine blades can weaken the blades, which could lead to premature failure of the turbine engine. In addition, erosion of the blades can change the shape of the blades, resulting in less efficient operation of the turbine engine.
Unfortunately, it is difficult to determine the degree of erosion of the blades without directly measuring the blades. And accessing the compressor and turbine blades to take such measurements is very difficult. As a result, operators and manufacturers estimate the useful life of the blades through analytic calculations. If such estimates are too conservative, it can result in premature replacement of the blades, which wastes time and money. If such estimates are too liberal, it can result in failure of a turbine engine, which would be even more costly.